Pressure platen means for a belt polishing or grinding machine



Sept. 22, 1959 w. FEURICH PRESSURE PLATEN MEANS FOR A BELT POLISHING OR GRINDING MACHINE Filed Feb. 21, 1958 United States Patent 0 "ic 2,904,931

PLATEN MEANS FOR A BELTPO'LISH- 5 RINDING MACHINE Werner Feurich, Ionsdorf, G Maschiuenbau Jonsdorr,

ermany, assignor to VEB Jonsdorf, Germany The present invention relates to platen grinding and Patented Sept. 22, 1959 numerals designate like or corresponding parts throughe out the several views, there is shown a work table 1 reciprocably movable in a horizontal "plane at right angle to the direction of movement of an abrasive belt 10, a rigid backing platen 2, having mounted thereon a resilient surface cover 3aof relatively soft cushioningma terial, such as sponge rubber, which presses in the working zone against an endless steel belt 4 looped around guide pulleys 5 and 6 and held in a longitudinally adjustable fixed position by said guide pulleys. A portion of steel belt 4 is provided with a cover 7 of cleat-like projections holding the endless abrasive belt 10 in dontact with the workpiece 13. Belt 10 is looped: around guide pulleys 11 and 12 at least one of which is driven in the conventional manner by an. electric motor or other prime mover whereby the abrasive belt 10 may be made polishing machines, an for platen grinding and polishing ma Machines of this type are equippe abrasive belt traveling over th speed. The belt is gui pulleys and is supported sure platen of metallic or may be equipped with a resilient surface coating or cover. polishing machines of a ic chambers which exerted by the abrasive de for raising d more particularly to platen means d with an endless k at considerable ded in a closed path by guide in the working zone by a presnon-metallic material which Platens for belt grinding and known type are equipped with permit adjustment of the pressure belt on the work piece. thepneumatic chambers opposite the feed end in the trailing edge of the w Another known type 0 equipped with a plurality which press the abrasive In other belt grinding mac oscillating movement 0 table in order to provi dependent of Because of the large abrasive belt, the belt temperature is instantially which leads to rapid we abrasive belt.

Provisions are ma from the side of the machine order to prevent damage to f belt grinding machines is air-actuated grinding shoes belt against the work piece. hines, a platen swings in an the entire width of the work de uniform grinding pressure inthe skill of the operator.

contact area between pressure the uniform application of pressure over the entire area of contact between th the abrasive belt, the the working zone with to overheating of the wor zone and results in an uneven grin An object of the pres platen means which fiat surface to the e work piece and grinding dust cannot escape from sufficient speed. This ag k and of the belt in the work cut invention is permit grindin very edge without dama the provision of g or polishing of a ct is to provide such platen means which work piece and of the belt.

the invention is the provision of ding and polishing machines which f maximum contact f the invent1 s which permit the escape of thus giving a cleaner the invention will from the following d drawings which illustrate a odiment, and whe lan view of a pref stationary back-up belt Fig. 2 is an elevational chine equipped with the ba Other objects an hereafter become more description of the annexe preferred emb erred embodiment of the of the invention,

view of a belt grinding mack-up belt of the invention,

Fig. 3 is an enlarg Referring now to to travel over the workpiece in the direction of the arrow shown in Fig. 2 at high speed. The position of belt 4 on pulleys 5 and 6 is arranged in such a manner that the end of the cleat cover 7 coincides precisely with. the leading edge 13 of the work piece which is to be ground or polished by abrasive belt 10. Work piece 13 is held in. proper alignment on Work table 1 by a guide stop 14 and isworked upon by abrasive belt 10. Belt 10 is backed up by platen means including a steel belt 4 with cleat cover 7 adjustable as indicated by the arrow in Fig.3, for precise alignment of theleadingiedge 13' of workpiece 13 with the limit 7 of the cleat cover 7.'

The above described device operates as follows:

Steel belt 4 has a canvas cover 8, ridge-shaped projec tions 7" of elastic material such as leather cleats, fas tened to steel belt 4 by means of rivets 9 which pass through the intermediate canvas cover. Longitudinal rows of spaced cleats are arranged along the edges of belt 4. The surface of belt 4 between the edges is provided with rows of spaced cleats arranged at an angle to the rows at the edges. The canvas cover 8 and cleats 7" cover only a portion of steel belt 4 and end abruptly along a straight limit line 7 transverse to the longitudinal direction of belt 4.

A work piece is fastened to the work table 1 and stop 14 is adjusted so that the edge 13 of the work piece is exactly at right angle to the plane of rotation of abrasive belt 10 and parallel to the direction of travel of work table 1. Pulleys 5 and 6 are then rotated and belt 4 shifted thereby until the cleat cover 7 of belt 4 extends across the entire width of the work piece 13 and the limit 7 of the cleat cover is precisely aligned with the leading edge 13 of the work piece. The position of belt 4 is fixed by suitably arresting pulleys 5 or 6. The motor actuating movement of the abrasive belt 10 is started and the work piece is passed under the belt for grinding or polishing in the usual manner. If necessary, the position of belt 4 may again be adjusted by means of pulleys 5 and 6 while the machine is running.

It is apparent that the area of pressure is precisely limited at the edge 13' of work piece 13 and that damage to the leading edge 13, that is, the edge exposed to the attack of the abrasive belt, which is a serious shortcoming of many types of platen grinding machines, is avoided or held to a minimum. The provision of individual ridge shaped elements or cleats backing up the abrasive belt reduces the area of maximum pressure between the belt and the work piece, thus reducing belt wear, avoiding excessive heating of belt and work, and permitting the accumulated grinding dust to escape. The steel belt 4 on which cleats 7" are mounted has been found to increase the useful life of the cleat cover 7 which is subject to shear forces by contact with the rapidly moving abrasive belt.

While a sponge rubber cushion 3, a steel belt 4, and

leather cleats 7 have been shown in the preferred embodv -metallic materials ansponge rubber, and that the choice of suitable mate- I or projections with which the surface of the stationary belt is equipped is very wide and depends among other things on the magnitude of the pressure that is to be transmitted by the projections, on the backing material of the abrasive belt and on its speed.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure, which do not constitute departures from the spirit and scope of the .inventionset forth on the appended claims.

What is claimed is:

1. In an abrasivegrinding machine having a Work face adapted to support and position a workpiece, an abrasive belt operably disposed opposite said work face, belt mounted within and stationary with respect to said abrasive belt, rigid backing means positioned in contact .with the inner side of said backing belt, and a plurality .of projections regularly disposed over a portion of the outer side of said backing belt, the construction and arrangement being such that the leading edge of the workpiece'coincides with the leading edge of said spaced pro- -jections.

2. An abrasive grinding machine comprising a work face adapted to support and position a workpiece, an abrasive belt operably disposed opposite said work face, a backing belt mounted within and stationary with respect to said abrasive belt, rigid backing means positioned in contact with the inner side of said backing belt, and a plurality of projections covering a portion of the outer side of said backing belt, the construction and arrangement being such that the leading edge of the workpiece coincides with the leading edge of said projections.

3. An abrasive grinding machine as in claim 2, further comprising a resilient surface cover disposed between said rigid backing means and said backing beltand secured to said rigid backing means.

4. An abrasivegrinding machine as in claim 2 wherein said projections have an elongated shape.

5-. An abrasive grinding machine as in claim 2, wherein said projections are regularly arranged on said backing belt in angular rows oblique to the edge of said back-up belt.

6. An abrasive grinding machine as in claim 2, wherein said projections are disposed to form a plurality of flat surfaces parallel tothe lower surface of said back-up belt. I 7. An abrasive grinding machine as in claim 2, wherein said projections have substantially parallel edges.

8. An abrasive grinding machine as in claim 2, wherein said projections are arranged in rows, two of said rows 1 References Cited in the file of this patent UNITED STATES PATENTS 829,191 Yarnell Aug. 21, 1906 830,116 Tyden Sept. 4, 1906 953,031 Hausman et al Mar. 29, 1910 1,043,194 Blevney Nov. 5, 1912 1,064,572 Trogdon' June 10, 1913 1,949,700 Turcott Mar. 6, 1934 1,978,149 Stevenson Oct. 23, 1934 2,624,160 Harper Jan. 6, 1953 

